fs/udf/dir.c

   1 /*
   2  * dir.c
   3  *
   4  * PURPOSE
   5  *  Directory handling routines for the OSTA-UDF(tm) filesystem.
   6  *
   7  * COPYRIGHT
   8  *      This file is distributed under the terms of the GNU General Public
   9  *      License (GPL). Copies of the GPL can be obtained from:
  10  *              ftp://prep.ai.mit.edu/pub/gnu/GPL
  11  *      Each contributing author retains all rights to their own work.
  12  *
  13  *  (C) 1998-2004 Ben Fennema
  14  *
  15  * HISTORY
  16  *
  17  *  10/05/98 dgb  Split directory operations into its own file
  18  *                Implemented directory reads via do_udf_readdir
  19  *  10/06/98      Made directory operations work!
  20  *  11/17/98      Rewrote directory to support ICBTAG_FLAG_AD_LONG
  21  *  11/25/98 blf  Rewrote directory handling (readdir+lookup) to support reading
  22  *                across blocks.
  23  *  12/12/98      Split out the lookup code to namei.c. bulk of directory
  24  *                code now in directory.c:udf_fileident_read.
  25  */
  26
  27 #include "udfdecl.h"
  28
  29 #include <linux/string.h>
  30 #include <linux/errno.h>
  31 #include <linux/mm.h>
  32 #include <linux/slab.h>
  33 #include <linux/buffer_head.h>
  34
  35 #include "udf_i.h"
  36 #include "udf_sb.h"
  37
  38 static int do_udf_readdir(struct inode *dir, struct file *filp,
  39                           filldir_t filldir, void *dirent)
  40 {
  41         struct udf_fileident_bh fibh = { .sbh = NULL, .ebh = NULL};
  42         struct fileIdentDesc *fi = NULL;
  43         struct fileIdentDesc cfi;
  44         int block, iblock;
  45         loff_t nf_pos = (filp->f_pos - 1) << 2;
  46         int flen;
  47         unsigned char *fname = NULL;
  48         unsigned char *nameptr;
  49         uint16_t liu;
  50         uint8_t lfi;
  51         loff_t size = udf_ext0_offset(dir) + dir->i_size;
  52         struct buffer_head *tmp, *bha[16];
  53         struct kernel_lb_addr eloc;
  54         uint32_t elen;
  55         sector_t offset;
  56         int i, num, ret = 0;
  57         unsigned int dt_type;
  58         struct extent_position epos = { NULL, 0, {0, 0} };
  59         struct udf_inode_info *iinfo;
  60
  61         if (nf_pos >= size)
  62                 goto out;
  63
  64         fname = kmalloc(UDF_NAME_LEN, GFP_NOFS);
  65         if (!fname) {
  66                 ret = -ENOMEM;
  67                 goto out;
  68         }
  69
  70         if (nf_pos == 0)
  71                 nf_pos = udf_ext0_offset(dir);
  72
  73         fibh.soffset = fibh.eoffset = nf_pos & (dir->i_sb->s_blocksize - 1);
  74         iinfo = UDF_I(dir);
  75         if (iinfo->i_alloc_type != ICBTAG_FLAG_AD_IN_ICB) {
  76                 if (inode_bmap(dir, nf_pos >> dir->i_sb->s_blocksize_bits,
  77                     &epos, &eloc, &elen, &offset)
  78                     != (EXT_RECORDED_ALLOCATED >> 30)) {
  79                         ret = -ENOENT;
  80                         goto out;
  81                 }
  82                 block = udf_get_lb_pblock(dir->i_sb, &eloc, offset);
  83                 if ((++offset << dir->i_sb->s_blocksize_bits) < elen) {
  84                         if (iinfo->i_alloc_type == ICBTAG_FLAG_AD_SHORT)
  85                                 epos.offset -= sizeof(struct short_ad);
  86                         else if (iinfo->i_alloc_type ==
  87                                         ICBTAG_FLAG_AD_LONG)
  88                                 epos.offset -= sizeof(struct long_ad);
  89                 } else {
  90                         offset = 0;
  91                 }
  92
  93                 if (!(fibh.sbh = fibh.ebh = udf_tread(dir->i_sb, block))) {
  94                         ret = -EIO;
  95                         goto out;
  96                 }
  97
  98                 if (!(offset & ((16 >> (dir->i_sb->s_blocksize_bits - 9)) - 1))) {
  99                         i = 16 >> (dir->i_sb->s_blocksize_bits - 9);
 100                         if (i + offset > (elen >> dir->i_sb->s_blocksize_bits))
 101                                 i = (elen >> dir->i_sb->s_blocksize_bits) - offset;
 102                         for (num = 0; i > 0; i--) {
 103                                 block = udf_get_lb_pblock(dir->i_sb, &eloc, offset + i);
 104                                 tmp = udf_tgetblk(dir->i_sb, block);
 105                                 if (tmp && !buffer_uptodate(tmp) && !buffer_locked(tmp))
 106                                         bha[num++] = tmp;
 107                                 else
 108                                         brelse(tmp);
 109                         }
 110                         if (num) {
 111                                 ll_rw_block(READA, num, bha);
 112                                 for (i = 0; i < num; i++)
 113                                         brelse(bha[i]);
 114                         }
 115                 }
 116         }
 117
 118         while (nf_pos < size) {
 119                 filp->f_pos = (nf_pos >> 2) + 1;
 120
 121                 fi = udf_fileident_read(dir, &nf_pos, &fibh, &cfi, &epos, &eloc,
 122                                         &elen, &offset);
 123                 if (!fi)
 124                         goto out;
 125
 126                 liu = le16_to_cpu(cfi.lengthOfImpUse);
 127                 lfi = cfi.lengthFileIdent;
 128
 129                 if (fibh.sbh == fibh.ebh) {
 130                         nameptr = fi->fileIdent + liu;
 131                 } else {
 132                         int poffset;    /* Unpaded ending offset */
 133
 134                         poffset = fibh.soffset + sizeof(struct fileIdentDesc) + liu + lfi;
 135
 136                         if (poffset >= lfi) {
 137                                 nameptr = (char *)(fibh.ebh->b_data + poffset - lfi);
 138                         } else {
 139                                 nameptr = fname;
 140                                 memcpy(nameptr, fi->fileIdent + liu,
 141                                        lfi - poffset);
 142                                 memcpy(nameptr + lfi - poffset,
 143                                        fibh.ebh->b_data, poffset);
 144                         }
 145                 }
 146
 147                 if ((cfi.fileCharacteristics & FID_FILE_CHAR_DELETED) != 0) {
 148                         if (!UDF_QUERY_FLAG(dir->i_sb, UDF_FLAG_UNDELETE))
 149                                 continue;
 150                 }
 151
 152                 if ((cfi.fileCharacteristics & FID_FILE_CHAR_HIDDEN) != 0) {
 153                         if (!UDF_QUERY_FLAG(dir->i_sb, UDF_FLAG_UNHIDE))
 154                                 continue;
 155                 }
 156
 157                 if (cfi.fileCharacteristics & FID_FILE_CHAR_PARENT) {
 158                         iblock = parent_ino(filp->f_path.dentry);
 159                         flen = 2;
 160                         memcpy(fname, "..", flen);
 161                         dt_type = DT_DIR;
 162                 } else {
 163                         struct kernel_lb_addr tloc = lelb_to_cpu(cfi.icb.extLocation);
 164
 165                         iblock = udf_get_lb_pblock(dir->i_sb, &tloc, 0);
 166                         flen = udf_get_filename(dir->i_sb, nameptr, fname, lfi);
 167                         dt_type = DT_UNKNOWN;
 168                 }
 169
 170                 if (flen && filldir(dirent, fname, flen, filp->f_pos,
 171                                     iblock, dt_type) < 0)
 172                         goto out;
 173         } /* end while */
 174
 175         filp->f_pos = (nf_pos >> 2) + 1;
 176
 177 out:
 178         if (fibh.sbh != fibh.ebh)
 179                 brelse(fibh.ebh);
 180         brelse(fibh.sbh);
 181         brelse(epos.bh);
 182         kfree(fname);
 183
 184         return ret;
 185 }
 186
 187 static int udf_readdir(struct file *filp, void *dirent, filldir_t filldir)
 188 {
 189         struct inode *dir = filp->f_path.dentry->d_inode;
 190         int result;
 191
 192         if (filp->f_pos == 0) {
 193                 if (filldir(dirent, ".", 1, filp->f_pos, dir->i_ino, DT_DIR) < 0) {
 194                         return 0;
 195                 }
 196                 filp->f_pos++;
 197         }
 198
 199         result = do_udf_readdir(dir, filp, filldir, dirent);
 200         return result;
 201 }
 202
 203 /* readdir and lookup functions */
 204 const struct file_operations udf_dir_operations = {
 205         .llseek                 = generic_file_llseek,
 206         .read                   = generic_read_dir,
 207         .readdir                = udf_readdir,
 208         .unlocked_ioctl         = udf_ioctl,
 209         .fsync                  = generic_file_fsync,
 210 };